The human body can tolerate relatively small changes in internal body core temperature; however, considerable fluctuations pose serious, potentially life-threatening, health risks. Significant changes in the core body temperature cause conditions ranging from mild weakness and fatigue to decreased performance, coma and death.
Although all walks of life are susceptible to the dangers and discomfort of fluctuations in internal body core temperature, as evidenced by the thousands of heat-related deaths in France in the summer of 2003, athletes are at particularly high risk as they are more often subjected to unusual temperature (especially heat) stress.
In recent years, there has been a high occurrence of death associated with heat-related illnesses (e.g., heat exhaustion, severe heat cramps and heat stroke). In the United States alone, over 300 deaths per year are attributable to heat-related illnesses. Athletes are particularly vulnerable to heat-related illnesses and discomfort. Every year millions of athletes and contestants participate in sports that require competing or practicing in hot, humid environments. Under such circumstances, the body is often overwhelmed with uncompensated heat stress, which can be fatal. Heat-related illness is second only to head injuries as a cause of death among athletes in the United States. Due to the heavy equipment and uniform required, football players have increased risks of suffering from heat stress problems.
Elevations in core temperature also promote sweating which aggravate exercise-induced hypovolemia and contribute to dehydration. A rise in core temperature is also associated with a decline in athletic performance. During 2001, a series of heat-related injuries and deaths in college and professional football players brought national attention to the critical dangers of exercising in excessive heat. The combination of extreme heat and strenuous exercise proved deadly for two top football players, Eraste Thomas Autin and Korey Stringer. During a workout in 102° heat, Eraste Thomas Autin, 18, incoming freshman and aspiring player for the University of Florida Gators, collapsed, fell into a coma and subsequently died. Within a month of Autin's death, Korey Stringer, 27, offensive lineman for the Minnesota Vikings, also fatally fell victim to a heat stroke during practice. Upon arrival at a Minnesota hospital, Stringer's body temperature was more than 108° causing his organs to fail and lead to his ultimate death. It is important to note that these individuals were involved in highly sophisticated athletic programs where tremendous effort is made to avoid such tragedies. Clearly, there is a critical need to identify and implement improved methods for avoiding overheating in athletes and contestants.
Traditionally, athletes have relied upon contact conductance (using cool, wet towels or ice packs) to promote cooling and reduce core body temperature. However, these methods may not be totally effective in preventing overheating, especially when attempting to cool down football players in full uniform. Fans and misters have also been found to be only partially effective. By these methods, the body's core temperature may not be reduced effectively enough, which can lead to damage to multiple organs, including the heart, kidney, brain and liver.
Excessively cold environmental conditions can also hinder peak [athletic] performance and may have severe health implications for athletes. Once body temperature falls below just ninety-four degrees Fahrenheit, the hypothalamus loses its ability to regulate body temperature properly and health problems begin to accelerate. Also, as body temperature decreases in cold weather, muscles insufficiently warmed-up are more prone to injury, blood clots more easily, which increases the risk of a coronary artery blockage and hypothermia may strike from the combination of frigid air and sweat. It is important that athletes and contestants protect themselves from these potential health safety hazards while competing in cold weather.
Conductive and/or convective heating may be used to achieve desired thermal heating of athletes, or specific body parts, e.g., kicker's leg or pitcher's arm, in cold weather conditions. Muscle injury may be minimized and athletic performance is improved by keeping vulnerable limbs warm in cold environments.
In a constant pursuit to protect the health and safety of athletes while participating in hot and/or cold weather sports activities, there are a number of inventions that have been designed to modulate an individual's internal core body temperature. Although these inventions appear to be somewhat useful and contribute to the art of the invention (e.g., U.S. Pat. Nos. 2,052,869; 4,026,299 and 6,119,474), they prove not to be ideal for use in certain activities and sports, such as football, for one reason or another (such as being cumbersome, heavyweight and/or unmanageable).
It is clear that in order to ensure safety and enhance performance, an athlete's physiologic adaptation to his/her environment would be greatly facilitated by use of an improved system for controlling core body temperature. The system does not necessarily need to utilize the Coanda effect and could be made as part of a garment and/or protective gear. The subject invention fulfills these and other needs.